Light treating means

ABSTRACT

A central circle of blue, translucent light filtering material is surrounded by an annular circle of clear transparent material which in turn is surrounded by an annular area of blue translucent light filtering material to form a filtered zone plate through which artificially produced light is filtered and mixed to provide a more natural white light having reduced glare and improved color resolution and illumination. In a preferred form, the clear area functions as a light aperture and the central and annular translucent areas cooperate to provide a filtered light which mixes with the light passing through the aperture. The clear and translucent areas are provided by a flat, transparent plate which is removably secured to the light emitting face of a sealed beam lamp. The lamp includes a resistive incandescent filament for providing a light source, a parabolic reflector for collimating light directed through the plate and an opaque, reflective curved light shield positioned between the light source and the plate for preventing light produced by said light source from traveling through the plate without first being reflected from the reflector. The translucent areas are formed of a thin coating of an acrylic ester lacquer dyed with iron blue pigment. The filtered and unfiltered light combine to produce a white light surrounded by a blue field.

United States Patent [191 Hulbert, Jr.

1 Aug. 21, 1973 LIGHT TREATING MEANS [76] Inventor: Clarence E. Hulbert,Jr., PO. Box

265, West Columbia, Tex. 77486 [22] Filed: Apr. 21, 1971 [21] Appl. No.:136,799

[52] U.S. Cl 240/4659, 240/7.l, 240/4l.3,

Primary Examiner-Richard L. Moses Attorney-Carlos A. Torres [57]ABSTRACT A central circle of blue, translucent light filtering materialis surrounded by an annular circle of clear transparent material whichin turn is surrounded by an annular area of blue translucent lightfiltering material to form a filtered zone plate through whichartificially produced light is filtered and mixed to provide a morenatural white light having reduced glare and improved color resolutionand illumination. In a preferred form, the clear area functions as alight aperture and the central and annular translucent areas cooperateto provide a filtered light which mixes with the light passing throughthe aperture. The clear and translucent areas are provided by a flat,transparent plate which is removably secured to the light emitting faceof a sealed beam lamp. The lamp includes a resistive incandescentfilament for providing a light source, a parabolic reflector forcollimating light directed through the plate and an opaque, reflectivecurved light shield positioned between the light source and the platefor preventing light produced by said light source from travelingthrough the plate without first being reflected from the reflector. Thetranslucent areas are formed of a thin coating of an acrylic esterlacquer dyed with iron blue pigment. The filtered and unfiltered lightcombine to produce a white light surrounded by a blue field.

15 Claims, 3 Drawing Figures Patented Aug. 21, 1973 I Clarence EHu/bertJ INVE N TOR 700 (MNOMETERS) 400 WAVELENGTH A TTURNEY LIGHT TREATINGMEANS BACKGROUND OF THE INVENTION 1. Field of the Invention The presentinvention relates to means for improving artificial illumination. Morespecifically, the present invention relates to an improved lighttreating means for producing an improved artificially produced whitelight which exhibits superior illuminating characteristics, particularlyin highly reflective environments such as found on water surfaces and infog.

2. Description of the Prior Art A variety of devices have been suggestedby the prior art for producing improved, non-glare illumination forvarious environmental conditions. One such prior art device includes asealed beam lamp having an opaque, reflective shield disposed betweenthe filament and the light emitting face of the beam. Light reflectedfrom a parabolic surface in the lamp is collimated and directed throughrefractor elements to form a horizontal, nondiffused light with sharpvertical and horizontal cutoffs. Another prior art teaching disclosesmeans providing diffuse lighting from a light aperture positioned at thefocal point of a display lens for directing a light beacon toward alimited viewing area.

US. Pat. No. 1,457,565 to Warrick discloses a headlight lens whichcarries a central translucent coating of silver surrounded by an annulartransparent ring. A parabolic reflector cooperates with a light sourceto collimate the light before it is directed through the lens. The netresult is a reduction in glare caused by permitting certain of the lightrays to pass directly through the lens from the light source andreflecting the remainder of the rays against the parabolic surfacebefore they are emitted.

By and large, the prior art known to applicant fails to disclose asuitable, low glare, artificially produced white light whichsatisfactorily reduces the reflection problems encountered in rain, fog,water and on water surfaces.

SUMMARY OF THE INVENTION In the preferred form of the present invention,a clear transparent aperture defined between blue translucent lighttransmitting areas cooperate to form a filter zone for producing lightbeams of two colors which combine to form a circular beam of asubstantially white, natural-like light surrounded by an annular bluelight field. The translucent blue areas are preferably provided by anacrylic ester lacquer with iron blue pigmentation to form two blue beamswhich combine with the beam from the aperture to produce a white lightset in a field of blue.

In the preferred form of the invention, a central circular area oftranslucent, blue filter material is surrounded by an annular clear ortransparent aperture area which in turn is surrounded by a secondannular area of translucent blue filter material. Preferably, the bluefilter material is coated on the surface of an uncolored, transparentglass plate with the thickness of the coating being regulated to controlthe wavelengths and intensity of the transmitted light which in turn arefunctions of the wavelengths and intensity of light produced by thesource. The width of the clear annular aperture area is varied tocontrol the amount of unfiltered light being mixed with the filteredlight. The plate is removably secured to a sealed beam lamp whichincludes a transparent, flat, light emitting face, a parabolicreflecting surface, a light source and a curved, reflective opaque lightshield positioned between the light source and the light emitting face.The dimensions of the central blue area establish the principle focalpoint for the central beam. Beyond this principle focal point of thelight treating means, the unfiltered light passing through thetransparent annular aperture area combines with the blue light passingthrough the translucent filter areas to form a central circular beam ofwhite light set in an annular blue light field. The combined light beamexhibits significantly improved illuminating characteristics includingimproved color illumination and, a reduction in specular and diffuselyreflected aberrations that cause glare in highly reflective environmentssuch as are encountered in fog, smog, rain and on the surface of water.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical, front elevationof the light treating means of the present invention;

FIG. 2 is a vertical section taken along the line 2-2 of FIG. 2; and

FIG. 3 is a graph showing relative spectral intensities of differentlight wavelengths found in light produced by the present invention andfound in untreated light.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring jointly to FIGS. 1 and2, the light treating means of the present invention is indicatedgenerally at 10. In its preferred form, the invention 10 includes asealed beam lamp indicated generally at 11 to which is removably secureda filtered zone, light treating face plate 12 formed from a suitablelight transmitting material such as clear, uncolored glass or othersuitable material. The lamp 1 1 includes a light source filament 1 1a, acurved, reflective, opaque light shield 1 lb, a transparent lightemitting glass face 110, a parabolic reflecting body 11d, and anevacuated area 1 la. The lamp is energized in a conventional fashion byapplying anelectrical potential across external terminals 11a and 11a".The parabolic reflector lid is provided with a reflective surface 1 1dand cooperates with the shield 1 lb which is provided with a curvedreflective surface 11b to collimate and direct light produced by thefilament through the transparent lamp face 11c. In the preferred form ofthe present invention, the face 11c and plate 12 are substantiallyplanar or flat.

The face plate 12 is removably secured to the body of the lamp 11 by anysuitable means such as a split metal ring or clamp 13. The clamp 13 maybe equipped with any suitable tightening or securing means such as anadjustable bolt 13a by which the clamp may be secured about or removedfrom the lamp 11.

The plate 12 includes a translucent filtering portion 12a, a transparentaperture portion 12b and a second translucent filtering portion 120. Asused in the specification and claims herein, the term translucent isemployed to designate a material which filters light and transmitsvisible light of certain wavelengths more readily than light of otherwavelengths. The term translucent as employed herein may also includetransparent, colored materials. The phrase clear transparent as usedherein is employed to designate clear material which transmits allwavelengths of visible light in substantially the same manner withoutattenuating or filtering. The portion 12a is a central circular areawhich is provided with a thin, blue translucent coating. The bluecoating provides preferential transmission of light wavelengths ofapproximately 500 nanometers which is substantially a blue light. Otherwavelenghts are attenuated or filtered by the coating. The area 12b isan annular area of clear, uncolored, transparent light transmittingglass which transmits substantially all wavelengths of visible light tothe same degree because of its clarity. The annular area 120 whichsurrounds and is concentric with both the area 12b and the circular area12a is also formed of a thin translucent blue coating. In the preferredform, the coating is formed by applying a thin (0.001") coat of a blueacrylic ester lacquer to the plate 12 followed by a sheet of a stretchedpolyvinyl alcohol (in the form of a liquid coating0.00l" thick-which islater heat shrinked) which in turn is covered by a second thin (0.001layer of acrylic ester lacquer to form a total coating thickness ofapproximately 0.003". It should be noted that the thickness and color ofthe coating is varied according to the intensity and type of the lightsource to control the filtering characteristics of the translucentfiltering areas to thereby provide the desired preferential transmissionof given light wavelengths. It is theorized that the sheet of stretchedpolyvinyl alcohol cooperates with the acrylic coatings so that the lighttransmitted through the translucent areas is partially polarized. Ifdesired, the intermediate polyvinyl alcohol sheet may be omitted. In thelatter case, the total coating would be approximately 2 mils thick for alamp having the characteristics of the lamp 11. A suitable acrylic esterlacquer with iron blue pigmentation which may be employed for thelacquer coatings is manufactured for use in aerosol containers by theSinclair Paint Company of Los Angeles, Calif. as aerosol glass tintL-l8-l34.

While the translucent areas 12a and 120 have been shown as being formedby thin surface coatings on the plate 12, it will be understood that thetranslucent areas may be formed as an integral part of the plate 12rather than as a coating, and if desired, may be a transparent materialwith a blue coloring. Moreover, if desired, the plate 12 may bedispensed with and the translucent areas may be formed directly on theclear glass of the light emitting face 11c. It will also be appreciatedthat the translucent areas may be formed as an integral part of thelight emitting face 110.

While the preferred form of the invention employs acrylic esters incombination with a stretched polyvinyl alcohol sheet, it will beappreciated that other suitable materials may also be employed. Thus,where polarization is desired, a dichrotic material may be used.Dichrotic materials are birefringent, doubly refracting, that.

is, one of the components of light passing through such material isabsorbed much more strongly than the other.

The translucent blue coating material formed as described functions topartially polarize the light transmitted through the translucent areasof the plate 12 and to filter the light by preferentially transmittingthose wavelengths of light which substantially correspond to the colorblue. The filtered light combines with the untreated light passingthrough the annular aperture area 12b at a point remote from the lightmeans 11, such point being dependent upon the dimensions of the areas12a, 12b and 12c. When combined,'the blue and unfiltered light emittedfrom the filament produce a central white light beam surrounded by anannular blue beam to form a light which is highly directional, producesgood color illumination, exhibits diffused diffraction spectra, and lowspecular reflection to improve resolution and image quality. The annularblue beam circumscribing the central beam contains a sharply peakingwavelength to provide sharp cut off of scattered light.

FIG. 3 illustrates results of measurements made with a lampincorporating the teachings of the present invention. In FIG. 3, threecurves are employed to show the relative intensity of treated anduntreated light having wavelengths ranging from approximately 350 to 700nanometers. The vertical axis of the graph of FIG. 3 represents therelative intensity of light having a given wavelength. The data has beennormalized at a wavelength of 700 nanometers.

The data represented in FIG. 3 was taken at ll feet from the filament ofa shielded filament G.E. No. 4435 bulb powered by a 12 volt source andrated at 75,000 candle power. A plate having translucent areas and aclear light aperture arranged as shown on the plate 12 was employed toproduce the treated light. A 3 mil thick coating of blue acrylic esterlacquer with an intermediate sheet of stretched polyvinyl alcohol wasemployed to form the translucent portions of the filtered zone plate inthe manner and with the materials previously described. The radii of theexternal circumferences of 12a, 12b and 12c in the plate employed toobtain the data of FIG. 3 were 1.475 inches, 2.075 inches and 3.625inches, respectively. The principle focal point for the central beamproduced by the plate 12 and employed in securing the data of FIG. 3 wasapproximately 7 feet, 8 inches. At and beyond this focal point, the beamformed by the lightpassing through the plate includes a central beam ofwhite light surrounded by an annular beam of blue light. In thefollowing description, the term central beam" is employed to designatethe light appearing in the circular area which would be occupied by thebeam of white light at a point 11 feet from the filter zone plate withthe plate in position over the face of the lamp. With the plate removed,the untreated central beam is the light appearing in the same circulararea at a point 1 1 feet from the filament. The term annular beam isemployed to designate the annular area of blue light surrounding thecircular white beam at ll feet from the plate with the plate in positionagainst the face of the bulb.

In FIG. 3, the solid line curve A represents the relative intensity oflight varying in wavelength from approximately 350 to 700 nanometerswhichappears in the untreated central beam with the filter plateremoved. Broken Iine curve B of FIG. 3 represents relative intensity oflight in the same wavelength range appearing in the annular blue beamwith the plate 12 in position. Dashed curve C represents relativeintensity of the light in the same wavelength range appearing in thecentral beam with the filter plate in position.

Thecurves of FIG. 3 illustrate the significant increase in relativespectral intensities for substantially all wave- It is theorized thatthe outstanding characteristics of artificially produced light treatedin accordance with the present invention are attributable to a naturalphenomenon occurring in primate color vision whereby the blue annularbeam produces peripheral light wavelengths to stimulate the rods of theeye through excitation in a manner to provide threshold sensitivity andincrease reception by the cones of the eye to thereby improve visualacuity. The filter zone plate 12 of the present invention filters theartificially produced light through the translucent areas 12a and 12cand transmits the untreated light without substantial alteration throughthe clear, uncolored transparent aperture area 1212. The area 12bfunctions as a Fresnel aperture. The focal point of the central beammixing area is the principle focus of the aperture and this length isdetermined by the diameter of the circular area 12a. The width of theaperture regulates the amount of mixing of blue and untreated light atand beyond the focal point of the lamp. As illustrated in FIG. 3, themixed treated and untreated light combine to produce light of increasedintensity which peaks and forms a wave motion approximating that ofnatural sunlight.

It will be understood that in obtaining optimum results, the coating onthe treated surfaces of the plate 12 must be controlled in thickness andcoloring in a manner which is determined by the absolute intensity ofthe light produced by the source (bulb candle power untreated) and therelative spectral intensities of the different light wavelengths presentin the light from the source. The Fresnel aperture may or may not assumean annular configuration but should have dimensions proportioned toregulate the amount of untreated light mixed with the filtered lightpassing through the treated surfaces. Brightness contrast is alsocontrolled by the transmittance of the treated filtering area which inturnin a filtering device formed by coatings-is controlled by thethickness of the coatings.

The reasons for the unusual results achieved by light produced accordingto the teachings of the present invention are not altogether understood.Basically, it is theorized that improved lighting is achieved by mixinglight in the wavelength range of 350 to 700 nanometers having relativeintensities following the curve A of FIG. 3 with light wavelengths inthe same range having relative intensities represented by the curve B.This combination alone or coupled with a beam configuraiton wherein acentral circular beam of white light is surrounded by an annular beam ofblue light produces unexpected results in illumination and imagequality.

The light treating means of the present invention has a wide range ofapplication and is particularly useful when employed in high reflectionenvironments such as are encountered on the water surface, in relativelydense fog or smog conditions, in rain and under water.

The foregoing'disclosure and description of the invention isillustrative and explanatory thereof, and various changes in the size,shape and materials as well as in the details of the illustratedconstruction may be made within the scope of the appended claims withoutdeparting from the spirit of the invention. Thus, by way of examplerather than limitation, the circular and annular areas may take onstraight rather than curved boundaries or the light filament may bereplaced by an are or gas discharge light source or other suitable lightsource. It will be understood also that suitable color or polarizingfilters may be employed with the present invention. Thus, the clearannular aperture 1211 may be replaced with a transparent, colored filterto produce a colored central beam in a blue light field. It is alsotheorized that the blue color in the translucent areas may be replacedwith another color to change the color of both the central beam and thesurrounding annular beam. These latter modifications are not consideredto be superior to the preferred form of the invention described indetail hereinbefore, however, based on the present conception of theunderlying operation of the invention such modifications are consideredto be within the scope thereof.

It should also be observed that the term focal point as employed hereindesignates the point where the light beams from the aperture and filterportions are superimposed and is not necessarily synonymous with theterm focus customarily applied to optical instruments such as telescopesand microscopes.

What is claimed is:

1. Light treating means comprising:

a. a source of artificially produced light containing substantially allwavelengths of visible light;

b. light transmitting means having light transmitting portionspositioned with respect to said source whereby light from said source istransmitted through said light transmitting means;

c. first and second light filtering portions included in said lighttransmitting portions each of which includes means for preferentialtransmission of visible light of a substantially blue color through saidI transmitting means; and

d. light aperture means disposed intermediate said first and secondlight filtering portions and included in said light transmitting meansfor transmission of light from said source through said aperture meanswhereby filtered light transmitted through said first and second lightfiltering portions is mixed with light transmitted through said aperturemeans to form a combined light at a preselected point remote from saidlight filtering portion.

2. Light treating means as defined in claim 1 wherein:

a. said first light filtering portion includes a central,

substantially circular area; and

b. said light aperture means includes a substantially annular lightaperture area formed concentrically about said circular area. a

3. Light treating means as defined in claim 2 wherein said second lightfiltering portion comprises a substantially annular area formedconcentrically about both said central circular area and said annularlight aperture area.

4. Light treating means as defined in claim 1 wherein a. reflectivemeans for directing light produced by said light source through saidlight transmitting means whereby light passing through said first lightfiltering portion and said aperture means is mixed at a point remotefrom said source; and

b. light shielding means disposed between said light source means andsaid light transmitting means for preventing light produced by saidlight source means from traveling through said light transmitting meanswithout first being reflected from said reflective means.

8. Light treating means as defined in claim 7 wherein:

a. said light source means includes a resistive electrical element forproducing light upon being energized by an electrical potential; and

b. said reflective means includes a parabolic reflector forsubstantially collimating light directed through said light transmittingmeans.

9. Light treating means as defined in claim 8 wherein:

a. said reflective means and said light source means are included in asealed beam lamp adapted to produce and direct light through a lightemitting face; and

b. said light transmitting means is removably secured over the lightemitting face of said lamp.

10. Light treating means as defined in claim 9 wherein said lightemitting face of said lamp and said light transmitting means aresubstantially planar.

11. Light treating means as defined in claim 1 wherein said first secondand light filtering portions include a surface coating of blue acrylicester lacquer to form a translucent area on said light transmittingmeans.

12. Light treating means as defined in claim 11 wherein said first andsecond light filtering portions include a thin blue acrylic estercoating covered by a thin sheet of a stretched polyvinyl alcohol whichin turn is covered by a thin coating of blue acrylic ester.

13. A method of producing improved natural-like light comprising mixinglight having characteristics which are substantially equivalent to thelight emitted by a 12 volt GE. 4435 bulb rated at 75,000 candle powerand transmitted through a filtered zone plate positioned adjacent andover the light emitting face of said bulb, said filtered zone platehaving a central, circular translucent filtering area with a radius of1.475 inches, surrounded by a concentric, annular, uncolored transparentarea having an outer radius of 2.075 inches which in turn is surroundedby a concentric, annular translucent filtering area having an outerradius of 3.625 inches, said translucent filtering areas being formed bya coating, 2 mils thick, carried on a thin plate of uncolored,transparent glass and formed by applying to said plate an acrylic esterlacquer with iron blue pigmentation, said lacquer being of the typemanufactured by Sinclair Paint Company of Los Angeles, Calif. as aerosolglass tint No. L-l8-134.

14. A method producing improved natural-like light comprising mixinglight in the wavelength range between approximately 350 and 700nanometers having substantially the relative intensities represented bythe curve B in FIG. 3 with light in said range having substantially therelative intensities represented by the curve A in FIG. 3.

15. A method as defined in claim 14 wherein said light is mixed to forma central circular beam of substantially white light set in an annularblue light field. l i

1. Light treating means comprising: a. a source of artificially producedlight containing substantially all wavelengths of visible light; b.light transmitting means having light transmitting portions positionedwith respect to said source whereby light from said source istransmitted through said light transmitting means; c. first and secondlight filtering portions included in said light transmitting portionseach of which includes means for preferential transmission of visiblelight of a substantially blue color through said transmitting means; andd. light aperture means disposed intermediate said first and secondlight filtering portions and included in said light transmitting meansfor transmission of light from said source through said aperture meanswhereby filtered light transmitted through said first and second lightfiltering portions is mixed with light transmitted through said aperturemeans to form a combined light at a preselected point remote from saidlight filtering portion.
 2. Light treating means as defined in claim 1wherein: a. said first light filtering portion includes a central,substantially circular area; and b. said light aperture means includes asubstantially annular light aperture area formed concentrically aboutsaid circular area.
 3. Light treating means as defined in claim 2wherein said second light filtering portion comprises a substantiallyannular area formed concentrically about both said central circular areaand said annular light aperture area.
 4. Light treating means as definedin claim 1 wherein said aperture means includes means fornon-preferential transmission of visible light of all wavelengths. 5.Light treating means as defined in claim 1 wherein said first lightfiltering portion includes means for preferential transmission of lightwavelengths of approximately 500 nanometers.
 6. Light treating means asdefined in claim 1 wherein said first light filtering portion includeslight polarizing means for at least partially polarizing lighttransmitted through said first light filtering portion.
 7. Lighttreating means as defined in claim 3 further including: a. reflectivemeans for directing light produced by said light source through saidlight transmitting means whereby light passing through said first lightfiltering portion and said aperture means is mixed at a point remotefrom said source; and b. light shielding means disposed between saidlight source means and said light transmitting means for preventinglight produced by said light source means from traveling through saidlight transmitting means without first being reflected from saidreflective means.
 8. Light treating means as defined in claim 7 wherein:a. said light source means includes a resistive electrical element forproducing light upon being energized by an electrical potential; and b.said reflective means includes a parabolic reflector for substantiallycollimating light directed through said light transmitting means. 9.Light treating means as defined in claim 8 wherein: a. said reflectivemeans and said light source means are included in a sealed beam lampadapted to produce and direct light through a light emitting face; andb. said light transmitting means is removably secured over the lightemitting face of said lamp.
 10. Light treating means as defined in claim9 wherein said light emitting face of said lamp and said lighttransmitting means are substantially planar.
 11. Light treating means asdefined in claim 1 wherein said first second and light filteringportions include a surface coating of blue acrylic ester lacquer to forma translucent area on said light transmitting means.
 12. Light treatingmeans as defined in claim 11 wherein said first and second lightfiltering portions include a thin blue acrylic ester coating covered bya thin sheet of a stretched polyvinyl alcohol which in turn is coveredby a thin coating of blue acrylic ester.
 13. A method of producingimproved natural-like light comprising mixing light havingcharacteristics which are substantially equivalent to the light emittedby a 12 volt G.E. -4435 bulb rated at 75,000 candle power andtransmitted through a filtered zone plate positioned adjacent and overthe light emitting face of said bulb, said filtered zone plate having acentral, circular translucent filtering area with a radius of 1.475inches, surrounded by a concentric, annular, uncolored transparent areahaving an outer radius of 2.075 inches which in turn is surrounded by aconcentric, annular, translucent filtering area having an outer radiusof 3.625 inches, said translucent filtering areas being formed by acoating, 2 mils thick, carried on a thin plate of uncolored, transparentglass and formed by applying to said plate an acrylic ester lacquer withiron blue pigmentation, said lacquer being of the type manufactured bySinclair Paint Company of Los Angeles, Calif. as aerosol glass tint No.L-18-134.
 14. A method producing improved natural-like light comprisingmixing light in the wavelength range between approximately 350 and 700nanometers having substantially the relative intensities represented bythe curve B in FIG. 3 with light in said range having substantially therelative intensities represented by the curve A in FIG.
 3. 15. A methodas defined in claim 14 wherein said light is mixed to form a centralcircular beam of substantially white light set in an annular blue lightfield.